ENSO Alert System Status: El Niño ADVISORY

My two cents worth.

..During this time of year, El Nino, or Winter, forecasts are still in what’s considered the Unpredictability period. Late Fall, is when the Forecasts really begin to hone in on what the upcoming Winter will likely bring.  This year there are several abnormalities to be considered in the long range outlook. A couple of examples are pictured below.

..  First off, the SST’s are 1.8c warmer than normal for the ENSO 3.4 Region. This is where the El Nino Forecasts are derived from for the West Coast of California. This year we are in what’s considered to be an El Nino State of the Ocean. Sea Surface Temperatures (SST’s) in the Equatorial Region 3.4,  are running well above normal, for this time of year.  Thus a strong, to very strong  El Nino forecast for our area is the current outlook. However, there are other factors that come into play that are making this El Nino outlook more difficult than normal. SST’s are warmer than normal in many other areas other than the ENSO 3.4 Region. So this will all have a part in the final outcome for this year’s Winter events. The medium range outlook as of today calls for a wet period through the end of November. Then as we head into January, through March, the current outlook is trending towards wetter  than normal for Central and SoCal.

..One of the many features we will be looking for is a resident area of Low pressure sitting off of the coast of Alaska. This will help to direct the Jet stream towards Central and Southern California, later this Winter. The Southern part of the Polar Jet will also be directed more to the Southern part of the State helping to bring warm and moist storms to our area. This can also be a recipe for heavy Spring snows for our local area. Typically during an El Nino year, the freezing levels run higher than normal through the Winter months.  But as we transition to Spring, cold air from the North can make it’s way South and mix with the wet moist Tropical air mass, and we get heavy wet snow locally during March.

..So as we head into the month of november, things should become a little more clear as far as what to expect. Long Range Forecasting is like dropping a plastic ball in a pool, and trying to figure out where it will be tomorrow.  RC


ENSO Alert System Status: El Niño Advisory

Synopsis: El Niño is anticipated to continue through the Northern Hemisphere spring (with a 62% chance during April-June 2024).

Above-average sea surface temperatures (SST) across the equatorial Pacific Ocean (Fig. 1), were indicative of a strong El Niño, with anomalies increasing in the central and east-central Pacific in the past month.  The latest weekly Niño index values were +1.4ºC in Niño-4, +1.8ºC in Niño-3.4, +2.1ºC in Niño-3, and +2.2ºC in Niño-1+2 (Fig. 2). Area-averaged subsurface temperatures anomalies increased slightly (Fig. 3) associated with the initiation of a downwelling oceanic Kelvin wave, which strengthened above-average subsurface temperatures in the central equatorial Pacific (Fig. 4). Low-level wind anomalies were westerly in the east-central Pacific, while upper-level wind anomalies were easterly in the western and central Pacific.  Convection/rainfall was enhanced around the International Date Line, extending into the eastern Pacific.  Suppressed convection/rainfall strengthened around Indonesia (Fig. 5). The equatorial Southern Oscillation Index (SOI) and the station-based SOI remained negative.  Collectively, the coupled ocean-atmosphere system reflected a growing El Niño.

The most recent IRI plume favors El Niño to continue through the Northern Hemisphere spring 2024 (Fig. 6).  Based on latest forecasts, there is a  greater than 55% chance of at least a “strong” El Niño (≥ 1.5°C in Niño-3.4 for a seasonal average) persisting through January-March 2024.  There is a 35% chance of this event becoming “historically strong” (≥ 2.0° C) for the November-January season.  Stronger El Niño events increase the likelihood of El Niño-related climate anomalies, but do not necessarily equate to strong impacts (see CPC seasonal outlooks for probabilities of temperature and precipitation).  In summary, El Niño is anticipated to continue through the Northern Hemisphere spring (with a 62% chance during April-June 2024; Fig. 7).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Additional perspectives and analysis are also available in an ENSO blog. A probabilistic strength forecast is available here. The next ENSO Diagnostics Discussion is scheduled for 14 December 2023. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: ncep.list.enso-update@noaa.gov.







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